Free online BMP to GIF converter

A program, document system, or older device may accept GIF images but reject BMP files, requiring conversion before upload or sharing. GIF can also reduce file size for icons, diagrams, screenshots, and other images with a limited color range.

What the BMP format is

BMP (Bitmap) is a raster format that stores image pixels, commonly with 1-bit, 4-bit, 8-bit, 24-bit, or 32-bit color data. Windows Paint and other Windows graphics utilities use BMP, and applications often create it when saving a basic Windows bitmap. BMP is simple for software to read, but most BMP files are uncompressed or use only limited compression, so they are usually larger than GIF, PNG, or JPEG files. BMP is used mainly by Windows software, basic image-editing workflows, legacy applications, and processes that need direct pixel data.

What the GIF format is

GIF (Graphics Interchange Format) stores each frame with an indexed palette of up to 256 colors. LZW compression is lossless for the indexed pixel data, which makes GIF efficient for logos, icons, diagrams, flat-color screenshots, and simple web graphics. GIF also supports animation and one transparent palette color, but it does not support continuous alpha transparency or the full color range of a photograph.

How to convert a BMP file to GIF

Using 101convert.com

1. Open the BMP-to-GIF converter on 101convert.com; it is free and requires no software installation.
2. Select or upload the .bmp file.
3. Choose GIF as the output format and start the conversion.
4. Download the .gif file and open it in an image viewer to check its dimensions, colors, and transparency.

Do not upload confidential images to any online service unless its handling and retention policies are acceptable for the file.

Using ImageMagick

Install ImageMagick, open a terminal in the folder containing the BMP, and run:

magick input.bmp output.gif

To force indexed-color reduction and remove metadata that is not required for display, run:

magick input.bmp -colors 256 -strip output.gif

ImageMagick maps colors to GIF's indexed palette automatically. Current installations normally use magick; older versions may use convert instead. For multiple numbered BMP frames, use a command such as:

magick -delay 10 -loop 0 frame*.bmp animation.gif

Here, -delay 10 sets 10 hundredths of a second between frames and -loop 0 repeats the animation indefinitely. Use consistently numbered filenames so the shell expands frames in the intended order.

Using GIMP

1. Open the BMP with File → Open.
2. Resize or edit the image if required. GIMP will convert colors to GIF's indexed palette during export.
3. Choose File → Export As, enter a filename ending in .gif, and select Export.
4. In the GIF export dialog, leave As animation disabled for a single image. Enable it only when separate layers are intended to become animation frames, then confirm with Export.

Quality and compatibility limits

If the BMP contains more than 256 colors, conversion must quantize the image. Photographs, gradients, and soft shading can therefore show banding, dithering, or altered colors. PNG is generally better for detailed lossless graphics, and JPEG is generally better for photographs; GIF is most suitable when the source already has flat areas and a small palette.

GIF transparency is binary: each pixel is either fully transparent or fully opaque. A BMP's 32-bit alpha channel cannot be preserved as continuous transparency, so soft shadows and antialiased edges may acquire a visible fringe against the transparent background.

A single BMP produces one GIF frame; changing the extension does not create animation. Animation requires multiple source frames or separate image layers, and some older viewers or document systems may not animate GIFs even though they can display the first frame.